Food is lost and wasted to varying extents across all stages of the food value chain and for all types of food, negatively impacting food security. In Nigeria, it has been revealed that a significant quantity of food is lost both before and after storage, with losses of up to 20-30% of all grains, 30-50% of roots and tubers, and a larger proportion of fruits and vegetables. Despite the Nigerian government's primary agricultural policy being to achieve food security and self sufficiency, the agricultural sector has steadily deteriorated over the years due to inadequate government attention. One of the primary causes of food insecurity, particularly in developing countries like Nigeria, is high postharvest losses and waste resulting from inadequate food processing and storage facilities, as well as negligence or a deliberate decision to discard food. This paper reviews the basic concept of food loss and waste, examines food security and the Nigerian situation, and discusses the challenges to food sufficiency, the implications and potential benefits of food loss, as well as some possible approaches to reducing food loss and waste in Nigeria. Thus, reducing food loss and waste is one of the leading global strategies for achieving a sustainable food future. Practical and cost-effective approaches could be implemented to attain mid-term gains once put into place. The review recommends the development of a food loss and waste measurement protocol and increased investments in reducing postharvest losses in Nigeria.